William miller



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IMEEOVEMENT iu'uosrtue MACHINE.

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TO ALL WHOM ICU-MAY CON-CERN: y

Beit known that' I, WILLIAD.; Militr., of Cincinnati, in the county ofHamilton, in the yState of Ohio,

have invented a new'and-'uscfnl Improvement in Hoisting Machines; andIdo hereby declare that the following is a full," clear, and exactdescription ofthe same, ,reference being had to the accompanyingdrawings, and te the letters of referencclmaried thereon, making a partof this specification. In the drawings-- Figure 1 represents aperspective,

Figure 2 a top,.and

Figure 3 a side View of my improved apparatus.

' ihc nature of my invention consists, first, in operating thesafety-pawls, bolts, or catches of a hoisting machine by toggle-levers,in connection with a spring, in such a manner that they levers will gainpower as the spring loses it,'thus securing the connection of the boltsor catches with the rack teeth, and the instantaneous stoppage of theplatform in a more prompt, certain, and effectual manner; and the natureof my invention consists, secondly', in providing a hoisting machinewith additional safety-stops to prevent damage when the rope is brokenat the drum from over-winding.

My first improvement may be thus described: A is a platform, attached towhich is the frame B B C, the bars B and B being grooved on their outersurface so as to embrace thc racks D D', and thus retain the frameandplatform in position while moving up and down. These bars areconnected at the top by a cross-piece, C,

which is furnished with a recess, E, and a slot, G. Through the slot therod H passes, having the lifting-ropel I attached -to its upper end,through the medium of the jointed connection K. To the 'lower end of rodH is attached the centre of the spring L L, the ends of which extend toeach side of therod, passing under the lower sides of the slides orbolt-cases M M. Through these slides the pawls or catches NN workfreely, having their outer ends bevelled to correspond to the teeth ofthe racks D D', and their inner ends jointed to the levers P P, which,in turn, are-jointed to rod H at such a point on the rod that'when theweight of the platform is removed from the rope I, the spring L L isrelaxed, and' `the pawls are in the rack teeth, the levers P P and4catches N N will form substantially a straight line. In operatingthis-device, the rope is drawn up, contracting the spring L L,withdrawing the bolts-N N from the rack teeth, and lifting the inner endof the levers P I into the recess E as shown by the red lines in fig. 2.If the rope should break', the spring would immediately retract, pullingdown the rod H, forcing the levers and bolts into line, and throwing thelatter promptly into the racks. It is evident that the power of thelevers is constantly increasing as they approach a straight line, whilethe power of the spring is decreasing with its gradual relaxation. I amaware lthat springs have been heretofore used in connection withsafety-pawls and racks upon hoisting machines, in one case to draw downa wedge which passes between the pawls and forces them outward, and inanother case where it is applied to depress the inner ends of the twobent levers-such as are shown in the patent of E. G. Otis, dated January15, 1861; but in the first case the descending wedge gains no power inits descent, and in the second the levers lose power by the gradualshortening of the arm to which the power is applied.

My second improvement is found in the catches S S, located just abovethe upper floor of the building in which the hoister is used, in theside pieces T T, so that while the platform may come to the level of thefloor without passing them, if by accident or negligence the platformshould be carried above the fioor and up to the drum or pulley, so as tobreak the rope, the catches, which are pressed back by the platform inits passage, are, as soon as it rises above them, immediately thrownforward by the springs X X, and form rests or stops by which theapparatus is caught as it descends, and kept from falling.

hat I claim as my invention, and desire to secure by Letters Patent, is-

1. The combination of rod H, levers I P, and pawls N N, jointedsubstantially as described with the racks O O and a spring, L,substantially as and for the purposes set forth.

it. The catches S S and spring X, or their equivalents, for the purposeof affording an automatic stop for' the platform, (to which they are not:ittached,) when the safety apparatus fails to act as described.

WM. MILLER.

Witnesses:

SAMUEL S. Frsnnu, Janus MOORE.

